In the treatment and care of turf such as grass or other ground covers of lawns, golf courses, softball fields, and the like, it is highly desirable to aerate the turf so as to enable air, moisture and nutrients to reach the roots of the grass, etc. The aeration of turf is generally performed by forming a pattern of holes in the turf. This tends to disturb the soil and roots beneath the surface of the ground cover and when moisture and fertilizers are applied to the turf, the root structure of the turf is able to directly absorb these nutrients and thereby the growth of the root structure is stimulated, making the turf healthier. Some of the prior art aerators typically have a plurality of coring tines which penetrate the soil and cut a generally cylindrical core or plug in the turf, and when the coring tines are removed from the turf they usually lift the core out of the ground, leaving a residue of cores of soil on the surface of the ground. The residue of cores of soil is undesirable on lawns and on playing fields such as golf courses and baseball fields where the condition of the surface of the turf is very important to the sports person. A type of core producing aerator is disclosed in U.S. Pat. No. 4,773,486.
As taught in my U.S. Pat. No. 5,029,652, a turf aerator has been developed which includes rotary hoes mounted about a laterally extending shaft which "walk" or rotate along the ground in response to forward movement of the aerator and which wobble when the shaft is rotated. This combination of movements causes the tines of the rotary hoes to form holes in the soil that are larger in lateral dimensions than the width of the tines, and the tines tend to penetrate the soil with less weight being required to force the tines into the soil than the previously known aerators. While the operation of my prior art aerator has proven satisfactory, the bearings which are required to create the wobbling of the rotary hoes tend to wear rapidly and become inoperative. This is because the ball bearings used in the prior art equipment are not capable of enduring the lateral forces encountered by the wobbling movements of the rotary hoes, especially when the tines are imbedded in dense soil and large lateral forces must be applied to the tines to push them laterally through the soil.
Accordingly it can be seen that it would be desirable to produce an apparatus which performs the function of aerating turf while significantly reducing compaction of the soil and without leaving cores of soil on the ground surface, and which forms openings in the surface of the turf and disturbs the soil to stimulate the growth of the root structure of the ground cover, and which includes a plurality of rotary hoes each having a bearing structure which is capable of enduring large and continual lateral wobbling forces as the tines of the rotary hoes walk through the soil and push the soil laterally.